Consulting report

Remote sensing of motor vehicle emissions in Krakow

On-road transportation in Poland is the second largest source of air pollution and the largest source of nitrogen oxides (NOx). This report provides an analysis of the real-world emissions data of Krakow’s vehicle fleet and compares the findings to measurements made in other European cities. The study used data from the CONOX database and from two additional remote sensing campaigns in Paris and London performed by the TRUE Initiative.

Vehicles measured in Krakow were, on average, two years older than vehicles in the CONOX database. This effect is more pronounced for early emission standards, for which vehicles in Krakow were up to 11 years older than the CONOX average. Measurements in Krakow were conducted during a heat wave, with median ambient temperatures near 30°C, making Krakow the hottest remote sensing campaign in the CONOX database. The estimated vehicle-specific power (VSP) values ranged from 2 to 10 kW/ton, and the median value of approximately 7 kW/ton was considerably lower than median engine load in the CONOX database.

Overall, NOx emissions from diesel passenger cars measured in Krakow were lower than in other European cities. NOx emissions from older petrol vehicles were generally somewhat higher than those in other datasets, a finding likely explained by the older fleet in Krakow. The NOx emissions from diesel vehicles remain generally several times higher than their type-approval limit, with the exception of Euro 6d-TEMP passenger cars, which were within the on-road Real Driving Emissions not-to-exceed threshold, but above regulatory laboratory limit.

Similar to findings from previous campaigns in London and Paris, CO emissions from light-duty petrol vehicles show a decrease in-line with advancing emission standards, while diesel CO emissions have remained consistently low and relatively stable. However, the data from Krakow suggests that CO emissions from petrol vehicles were considerably higher than in previous campaigns, with older vehicles in service being the likely cause.

The findings confirm the overall efficacy of diesel particulate filters since the introduction of the  Euro 5 light-duty vehicle standard, with vehicles predating it exhibiting the highest PM emission levels. Moreover, Krakow emission levels were consistently lower than the averages from other campaigns, a phenomenon which is partially explained by the test conditions favoring lower engine load.

The Krakow remote sensing campaign revealed that urban NOx emissions from diesel engines generally exceed petrol levels by several times, or at best by 50% for the newest vehicles. In addition, the oldest vehicles contribute disproportionately to air pollution levels due to more lenient emission standards. This is further compounded by the general deterioration of petrol emission reduction strategies through vehicle aging. This problem may be even more pronounced in the Polish fleet, which is, on average, four years older than that of the Krakow metropolitan area.